/*
   * IguanaWorks USB IR Transceiver support
   *
   * Copyright (C) 2012 Sean Young <sean@mess.org>
   *
   * This program is free software; you can redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; either version 2 of the License, or
   * (at your option) any later version.
   *
   * This program is distributed in the hope that it will be useful,
   * but WITHOUT ANY WARRANTY; without even the implied warranty of
   * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   * GNU General Public License for more details.
   *
   * You should have received a copy of the GNU General Public License
   * along with this program; if not, write to the Free Software
   * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
   */
  
  #include <linux/device.h>
  #include <linux/kernel.h>
  #include <linux/module.h>
  #include <linux/usb.h>
  #include <linux/usb/input.h>
  #include <linux/slab.h>
  #include <linux/completion.h>
  #include <media/rc-core.h>
  
  #define DRIVER_NAME "iguanair"
  #define BUF_SIZE 152
  
  struct iguanair {
  	struct rc_dev *rc;
  
  	struct device *dev;
  	struct usb_device *udev;
  
  	uint16_t version;
  	uint8_t bufsize;
  	uint8_t cycle_overhead;
  
  	struct mutex lock;
  
  	/* receiver support */
  	bool receiver_on;
  	dma_addr_t dma_in, dma_out;
  	uint8_t *buf_in;
  	struct urb *urb_in, *urb_out;
  	struct completion completion;
  
  	/* transmit support */
  	bool tx_overflow;
  	uint32_t carrier;
  	struct send_packet *packet;
  
  	char name[64];
  	char phys[64];
  };
  
  #define CMD_NOP			0x00
  #define CMD_GET_VERSION		0x01
  #define CMD_GET_BUFSIZE		0x11
  #define CMD_GET_FEATURES	0x10
  #define CMD_SEND		0x15
  #define CMD_EXECUTE		0x1f
  #define CMD_RX_OVERFLOW		0x31
  #define CMD_TX_OVERFLOW		0x32
  #define CMD_RECEIVER_ON		0x12
  #define CMD_RECEIVER_OFF	0x14
  
  #define DIR_IN			0xdc
  #define DIR_OUT			0xcd
  
  #define MAX_IN_PACKET		8u
  #define MAX_OUT_PACKET		(sizeof(struct send_packet) + BUF_SIZE)
  #define TIMEOUT			1000
  #define RX_RESOLUTION		21333
  
  struct packet {
  	uint16_t start;
  	uint8_t direction;
  	uint8_t cmd;
  };
  
  struct send_packet {
  	struct packet header;
  	uint8_t length;
  	uint8_t channels;
  	uint8_t busy7;
  	uint8_t busy4;
  	uint8_t payload[0];
  };
  
  static void process_ir_data(struct iguanair *ir, unsigned len)
  {
  	if (len >= 4 && ir->buf_in[0] == 0 && ir->buf_in[1] == 0) {
  		switch (ir->buf_in[3]) {
  		case CMD_GET_VERSION:
  			if (len == 6) {
  				ir->version = (ir->buf_in[5] << 8) |
  							ir->buf_in[4];
  				complete(&ir->completion);
  			}
  			break;
  		case CMD_GET_BUFSIZE:
  			if (len >= 5) {
  				ir->bufsize = ir->buf_in[4];
  				complete(&ir->completion);
  			}
  			break;
  		case CMD_GET_FEATURES:
  			if (len > 5) {
  				ir->cycle_overhead = ir->buf_in[5];
  				complete(&ir->completion);
  			}
  			break;
  		case CMD_TX_OVERFLOW:
  			ir->tx_overflow = true;
  		case CMD_RECEIVER_OFF:
  		case CMD_RECEIVER_ON:
  		case CMD_SEND:
  			complete(&ir->completion);
  			break;
  		case CMD_RX_OVERFLOW:
  			dev_warn(ir->dev, "receive overflow
  ");
  			ir_raw_event_reset(ir->rc);
  			break;
  		default:
  			dev_warn(ir->dev, "control code %02x received
  ",
  							ir->buf_in[3]);
  			break;
  		}
  	} else if (len >= 7) {
  		DEFINE_IR_RAW_EVENT(rawir);
  		unsigned i;
  		bool event = false;
  
  		init_ir_raw_event(&rawir);
  
  		for (i = 0; i < 7; i++) {
  			if (ir->buf_in[i] == 0x80) {
  				rawir.pulse = false;
  				rawir.duration = US_TO_NS(21845);
  			} else {
  				rawir.pulse = (ir->buf_in[i] & 0x80) == 0;
  				rawir.duration = ((ir->buf_in[i] & 0x7f) + 1) *
  								 RX_RESOLUTION;
  			}
  
  			if (ir_raw_event_store_with_filter(ir->rc, &rawir))
  				event = true;
  		}
  
  		if (event)
  			ir_raw_event_handle(ir->rc);
  	}
  }
  
  static void iguanair_rx(struct urb *urb)
  {
  	struct iguanair *ir;
  	int rc;
  
  	if (!urb)
  		return;
  
  	ir = urb->context;
  	if (!ir) {
  		usb_unlink_urb(urb);
  		return;
  	}
  
  	switch (urb->status) {
  	case 0:
  		process_ir_data(ir, urb->actual_length);
  		break;
  	case -ECONNRESET:
  	case -ENOENT:
  	case -ESHUTDOWN:
  		usb_unlink_urb(urb);
  		return;
  	case -EPIPE:
  	default:
  		dev_dbg(ir->dev, "Error: urb status = %d
  ", urb->status);
  		break;
  	}
  
  	rc = usb_submit_urb(urb, GFP_ATOMIC);
  	if (rc && rc != -ENODEV)
  		dev_warn(ir->dev, "failed to resubmit urb: %d
  ", rc);
  }
  
  static void iguanair_irq_out(struct urb *urb)
  {
  	struct iguanair *ir = urb->context;
  
  	if (urb->status)
  		dev_dbg(ir->dev, "Error: out urb status = %d
  ", urb->status);
  
  	/* if we sent an nop packet, do not expect a response */
  	if (urb->status == 0 && ir->packet->header.cmd == CMD_NOP)
  		complete(&ir->completion);
  }
  
  static int iguanair_send(struct iguanair *ir, unsigned size)
  {
  	int rc;
  
  	reinit_completion(&ir->completion);
  
  	ir->urb_out->transfer_buffer_length = size;
  	rc = usb_submit_urb(ir->urb_out, GFP_KERNEL);
  	if (rc)
  		return rc;
  
  	if (wait_for_completion_timeout(&ir->completion, TIMEOUT) == 0)
  		return -ETIMEDOUT;
  
  	return rc;
  }
  
  static int iguanair_get_features(struct iguanair *ir)
  {
  	int rc;
  
  	/*
  	 * On cold boot, the iguanair initializes on the first packet
  	 * received but does not process that packet. Send an empty
  	 * packet.
  	 */
  	ir->packet->header.start = 0;
  	ir->packet->header.direction = DIR_OUT;
  	ir->packet->header.cmd = CMD_NOP;
  	iguanair_send(ir, sizeof(ir->packet->header));
  
  	ir->packet->header.cmd = CMD_GET_VERSION;
  	rc = iguanair_send(ir, sizeof(ir->packet->header));
  	if (rc) {
  		dev_info(ir->dev, "failed to get version
  ");
  		goto out;
  	}
  
  	if (ir->version < 0x205) {
  		dev_err(ir->dev, "firmware 0x%04x is too old
  ", ir->version);
  		rc = -ENODEV;
  		goto out;
  	}
  
  	ir->bufsize = 150;
  	ir->cycle_overhead = 65;
  
  	ir->packet->header.cmd = CMD_GET_BUFSIZE;
  
  	rc = iguanair_send(ir, sizeof(ir->packet->header));
  	if (rc) {
  		dev_info(ir->dev, "failed to get buffer size
  ");
  		goto out;
  	}
  
  	if (ir->bufsize > BUF_SIZE) {
  		dev_info(ir->dev, "buffer size %u larger than expected
  ",
  								ir->bufsize);
  		ir->bufsize = BUF_SIZE;
  	}
  
  	ir->packet->header.cmd = CMD_GET_FEATURES;
  
  	rc = iguanair_send(ir, sizeof(ir->packet->header));
  	if (rc)
  		dev_info(ir->dev, "failed to get features
  ");
  out:
  	return rc;
  }
  
  static int iguanair_receiver(struct iguanair *ir, bool enable)
  {
  	ir->packet->header.start = 0;
  	ir->packet->header.direction = DIR_OUT;
  	ir->packet->header.cmd = enable ? CMD_RECEIVER_ON : CMD_RECEIVER_OFF;
  
  	if (enable)
  		ir_raw_event_reset(ir->rc);
  
  	return iguanair_send(ir, sizeof(ir->packet->header));
  }
  
  /*
   * The iguanair creates the carrier by busy spinning after each half period.
   * This is counted in CPU cycles, with the CPU running at 24MHz. It is
   * broken down into 7-cycles and 4-cyles delays, with a preference for
   * 4-cycle delays, minus the overhead of the loop itself (cycle_overhead).
   */
  static int iguanair_set_tx_carrier(struct rc_dev *dev, uint32_t carrier)
  {
  	struct iguanair *ir = dev->priv;
  
  	if (carrier < 25000 || carrier > 150000)
  		return -EINVAL;
  
  	mutex_lock(&ir->lock);
  
  	if (carrier != ir->carrier) {
  		uint32_t cycles, fours, sevens;
  
  		ir->carrier = carrier;
  
  		cycles = DIV_ROUND_CLOSEST(24000000, carrier * 2) -
  							ir->cycle_overhead;
  
  		/*
  		 * Calculate minimum number of 7 cycles needed so
  		 * we are left with a multiple of 4; so we want to have
  		 * (sevens * 7) & 3 == cycles & 3
  		 */
  		sevens = (4 - cycles) & 3;
  		fours = (cycles - sevens * 7) / 4;
  
  		/*
  		 * The firmware interprets these values as a relative offset
  		 * for a branch. Immediately following the branches, there
  		 * 4 instructions of 7 cycles (2 bytes each) and 110
  		 * instructions of 4 cycles (1 byte each). A relative branch
  		 * of 0 will execute all of them, branch further for less
  		 * cycle burning.
  		 */
  		ir->packet->busy7 = (4 - sevens) * 2;
  		ir->packet->busy4 = 110 - fours;
  	}
  
  	mutex_unlock(&ir->lock);
  
  	return carrier;
  }
  
  static int iguanair_set_tx_mask(struct rc_dev *dev, uint32_t mask)
  {
  	struct iguanair *ir = dev->priv;
  
  	if (mask > 15)
  		return 4;
  
  	mutex_lock(&ir->lock);
  	ir->packet->channels = mask << 4;
  	mutex_unlock(&ir->lock);
  
  	return 0;
  }
  
  static int iguanair_tx(struct rc_dev *dev, unsigned *txbuf, unsigned count)
  {
  	struct iguanair *ir = dev->priv;
  	uint8_t space;
  	unsigned i, size, periods, bytes;
  	int rc;
  
  	mutex_lock(&ir->lock);
  
  	/* convert from us to carrier periods */
  	for (i = space = size = 0; i < count; i++) {
  		periods = DIV_ROUND_CLOSEST(txbuf[i] * ir->carrier, 1000000);
  		bytes = DIV_ROUND_UP(periods, 127);
  		if (size + bytes > ir->bufsize) {
  			rc = -EINVAL;
  			goto out;
  		}
  		while (periods) {
  			unsigned p = min(periods, 127u);
  			ir->packet->payload[size++] = p | space;
  			periods -= p;
  		}
  		space ^= 0x80;
  	}
  
  	ir->packet->header.start = 0;
  	ir->packet->header.direction = DIR_OUT;
  	ir->packet->header.cmd = CMD_SEND;
  	ir->packet->length = size;
  
  	ir->tx_overflow = false;
  
  	rc = iguanair_send(ir, sizeof(*ir->packet) + size);
  
  	if (rc == 0 && ir->tx_overflow)
  		rc = -EOVERFLOW;
  
  out:
  	mutex_unlock(&ir->lock);
  
  	return rc ? rc : count;
  }
  
  static int iguanair_open(struct rc_dev *rdev)
  {
  	struct iguanair *ir = rdev->priv;
  	int rc;
  
  	mutex_lock(&ir->lock);
  
  	rc = iguanair_receiver(ir, true);
  	if (rc == 0)
  		ir->receiver_on = true;
  
  	mutex_unlock(&ir->lock);
  
  	return rc;
  }
  
  static void iguanair_close(struct rc_dev *rdev)
  {
  	struct iguanair *ir = rdev->priv;
  	int rc;
  
  	mutex_lock(&ir->lock);
  
  	rc = iguanair_receiver(ir, false);
  	ir->receiver_on = false;
  	if (rc && rc != -ENODEV)
  		dev_warn(ir->dev, "failed to disable receiver: %d
  ", rc);
  
  	mutex_unlock(&ir->lock);
  }
  
  static int iguanair_probe(struct usb_interface *intf,
  			  const struct usb_device_id *id)
  {
  	struct usb_device *udev = interface_to_usbdev(intf);
  	struct iguanair *ir;
  	struct rc_dev *rc;
  	int ret, pipein, pipeout;
  	struct usb_host_interface *idesc;
  
  	ir = kzalloc(sizeof(*ir), GFP_KERNEL);
  	rc = rc_allocate_device();
  	if (!ir || !rc) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	ir->buf_in = usb_alloc_coherent(udev, MAX_IN_PACKET, GFP_KERNEL,
  								&ir->dma_in);
  	ir->packet = usb_alloc_coherent(udev, MAX_OUT_PACKET, GFP_KERNEL,
  								&ir->dma_out);
  	ir->urb_in = usb_alloc_urb(0, GFP_KERNEL);
  	ir->urb_out = usb_alloc_urb(0, GFP_KERNEL);
  
  	if (!ir->buf_in || !ir->packet || !ir->urb_in || !ir->urb_out) {
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	idesc = intf->altsetting;
  
  	if (idesc->desc.bNumEndpoints < 2) {
  		ret = -ENODEV;
  		goto out;
  	}
  
  	ir->rc = rc;
  	ir->dev = &intf->dev;
  	ir->udev = udev;
  	mutex_init(&ir->lock);
  
  	init_completion(&ir->completion);
  	pipeout = usb_sndintpipe(udev,
  				idesc->endpoint[1].desc.bEndpointAddress);
  	usb_fill_int_urb(ir->urb_out, udev, pipeout, ir->packet, MAX_OUT_PACKET,
  						iguanair_irq_out, ir, 1);
  	ir->urb_out->transfer_dma = ir->dma_out;
  	ir->urb_out->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
  
  	pipein = usb_rcvintpipe(udev, idesc->endpoint[0].desc.bEndpointAddress);
  	usb_fill_int_urb(ir->urb_in, udev, pipein, ir->buf_in, MAX_IN_PACKET,
  							 iguanair_rx, ir, 1);
  	ir->urb_in->transfer_dma = ir->dma_in;
  	ir->urb_in->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;
  
  	ret = usb_submit_urb(ir->urb_in, GFP_KERNEL);
  	if (ret) {
  		dev_warn(&intf->dev, "failed to submit urb: %d
  ", ret);
  		goto out;
  	}
  
  	ret = iguanair_get_features(ir);
  	if (ret)
  		goto out2;
  
  	snprintf(ir->name, sizeof(ir->name),
  		"IguanaWorks USB IR Transceiver version 0x%04x", ir->version);
  
  	usb_make_path(ir->udev, ir->phys, sizeof(ir->phys));
  
  	rc->input_name = ir->name;
  	rc->input_phys = ir->phys;
  	usb_to_input_id(ir->udev, &rc->input_id);
  	rc->dev.parent = &intf->dev;
  	rc->driver_type = RC_DRIVER_IR_RAW;
  	rc->allowed_protocols = RC_BIT_ALL;
  	rc->priv = ir;
  	rc->open = iguanair_open;
  	rc->close = iguanair_close;
  	rc->s_tx_mask = iguanair_set_tx_mask;
  	rc->s_tx_carrier = iguanair_set_tx_carrier;
  	rc->tx_ir = iguanair_tx;
  	rc->driver_name = DRIVER_NAME;
  	rc->map_name = RC_MAP_RC6_MCE;
  	rc->timeout = MS_TO_NS(100);
  	rc->rx_resolution = RX_RESOLUTION;
  
  	iguanair_set_tx_carrier(rc, 38000);
  	iguanair_set_tx_mask(rc, 0);
  
  	ret = rc_register_device(rc);
  	if (ret < 0) {
  		dev_err(&intf->dev, "failed to register rc device %d", ret);
  		goto out2;
  	}
  
  	usb_set_intfdata(intf, ir);
  
  	return 0;
  out2:
  	usb_kill_urb(ir->urb_in);
  	usb_kill_urb(ir->urb_out);
  out:
  	if (ir) {
  		usb_free_urb(ir->urb_in);
  		usb_free_urb(ir->urb_out);
  		usb_free_coherent(udev, MAX_IN_PACKET, ir->buf_in, ir->dma_in);
  		usb_free_coherent(udev, MAX_OUT_PACKET, ir->packet,
  								ir->dma_out);
  	}
  	rc_free_device(rc);
  	kfree(ir);
  	return ret;
  }
  
  static void iguanair_disconnect(struct usb_interface *intf)
  {
  	struct iguanair *ir = usb_get_intfdata(intf);
  
  	rc_unregister_device(ir->rc);
  	usb_set_intfdata(intf, NULL);
  	usb_kill_urb(ir->urb_in);
  	usb_kill_urb(ir->urb_out);
  	usb_free_urb(ir->urb_in);
  	usb_free_urb(ir->urb_out);
  	usb_free_coherent(ir->udev, MAX_IN_PACKET, ir->buf_in, ir->dma_in);
  	usb_free_coherent(ir->udev, MAX_OUT_PACKET, ir->packet, ir->dma_out);
  	kfree(ir);
  }
  
  static int iguanair_suspend(struct usb_interface *intf, pm_message_t message)
  {
  	struct iguanair *ir = usb_get_intfdata(intf);
  	int rc = 0;
  
  	mutex_lock(&ir->lock);
  
  	if (ir->receiver_on) {
  		rc = iguanair_receiver(ir, false);
  		if (rc)
  			dev_warn(ir->dev, "failed to disable receiver for suspend
  ");
  	}
  
  	usb_kill_urb(ir->urb_in);
  	usb_kill_urb(ir->urb_out);
  
  	mutex_unlock(&ir->lock);
  
  	return rc;
  }
  
  static int iguanair_resume(struct usb_interface *intf)
  {
  	struct iguanair *ir = usb_get_intfdata(intf);
  	int rc = 0;
  
  	mutex_lock(&ir->lock);
  
  	rc = usb_submit_urb(ir->urb_in, GFP_KERNEL);
  	if (rc)
  		dev_warn(&intf->dev, "failed to submit urb: %d
  ", rc);
  
  	if (ir->receiver_on) {
  		rc = iguanair_receiver(ir, true);
  		if (rc)
  			dev_warn(ir->dev, "failed to enable receiver after resume
  ");
  	}
  
  	mutex_unlock(&ir->lock);
  
  	return rc;
  }
  
  static const struct usb_device_id iguanair_table[] = {
  	{ USB_DEVICE(0x1781, 0x0938) },
  	{ }
  };
  
  static struct usb_driver iguanair_driver = {
  	.name =	DRIVER_NAME,
  	.probe = iguanair_probe,
  	.disconnect = iguanair_disconnect,
  	.suspend = iguanair_suspend,
  	.resume = iguanair_resume,
  	.reset_resume = iguanair_resume,
  	.id_table = iguanair_table,
  	.soft_unbind = 1	/* we want to disable receiver on unbind */
  };
  
  module_usb_driver(iguanair_driver);
  
  MODULE_DESCRIPTION("IguanaWorks USB IR Transceiver");
  MODULE_AUTHOR("Sean Young <sean@mess.org>");
  MODULE_LICENSE("GPL");
  MODULE_DEVICE_TABLE(usb, iguanair_table);